Shear attachment for power units



Sept 23, 11941- G. MCHENRY SHEAR ATTACHMENT FOR POWER UNITS Filed Nqv. 19, 1938 '5j INVENTOR. GAI/L NS/#WKK BY ,Kif j, A

ORNEYS.

Patented Sept. 23, 1941 UNITED STATES PATENT oEFl-CE 2,256,779 SHEAR ATTACHMENT FOR POWER UNITS l Gail McHenry, Muncie, Ind. Application November 19, 1938, Serial No. 241,315 3 Claims.` (Cl. 30-228) This invention relates to shear attachment for portable power units.

The chief object of this invention is to -provide a sheet cutting attachment, adaptedv for ready attachment to and detachment from such portable power units, such as electric drills and like which have a chuck for the interchangeable reception of different size drills, bits, taps, screw drivers and the like.

One chief feature of this invention resides in the incorporation of a driven element in the attachment which is receivable by the electric power unit chuck.

Another chief feature of this invention resides in the incorporation of universally adjustable means for rigidly associating the major portion of the attachment to any one of many styles and kinds of electric power units of the character indicated and now upon the market.

A further chief feature of the invention resides in incorporating in the major portion of the attachment first, a reduction drive devoid of gears and having a minimum of friction, and second, a reciprocating type shear.

A further feature of the inventionresides in incorporating with the stationaryshear, an extension at one end, and another portionpppositely positioned relative to the stationary shear portion, whereby the sheet metal being sheared is held straight and is prevented from binding upon or twisting the movable shearing member.

Other objects and features will be set forth more fully hereinafter.

Ihe full nature of the invention will be understood from the accompanying drawing and the following description and claims:

In Fig. 1, the numeral I indicates the main body portion of a hand or portable type power unit enclosing an electric motor, not shown. A

y handle or hand grip II. herein serves as a guard and support for the current supply I2 to the motor. An extension I3 rotatably supports the motor rotatable chuck I4 having the jaws I5. All of the aforesaid constitutes an illustrative embodiment of a conventional or standard portable power unit of the character indicated.

The major portion of the shear attachment is indicated by letter A in Fig. 1 and from it pro- `iects shaft I6 receivable by chuck'jaws l5 for rotation by the motor. Enveloping the body I'll is an adjustable clamp-on type of band I1, see adjustment I8, which includes the socket portion I9 having bore 20 therethrough and a locking thumb screw 2 I. A support rod, or the like, 22 has one=end slidably receivable by the bore 20 and rigidly anchored in the socket by the thumb screw. The opposite end of the rod is detachably and rigidly connected to the attachment proper A by `Reference now will be had more especially to In the drawing, Fig. 1 is a side elevation of a conventional portable or hand held and if desired controlled power unit with the attachment embodying the inventionapplied thereto.

Fig. 2 is an enlarged side elevation of the major portion of the attachment, parts being broken away and shown in vertical section to show more clearly other and interior parts.

Fig. 3 is a front view of the attachment shown in Fig. 2 with cover plate removed and similar parts are broken away to show other parts in section.

Fig. 4 is a transverse sectional view taken on line 4-4 of Fig. 3 and in the direction of the arrows.

Fig. 5 is a sectional view taken on line 5-5 of Fig. 4 in the direction of the arrows.

Fig. 6 is a view similar to Fig. 4 and of a modified form of sheet support.

Figs. 2 to 5, inclusive. In said figures, the body portion 25 includes two side walls 2'I from one of which extends downwardly a rearwardly and inwardly directed extension 28. The latter then extends forwardly as at 29 and constitutes a footA structure.

A cover plate 30 is suitably secured to. the body portion as at 3l. This forms a guide channel in which is slidably mounted reciprocable member 32. The cover plate and back wall are apertured as at 33 and therein is mounted aligned case-hardened bushings 34 which rotatably supports spaced portions of shaft I 6, see Fig. 2.

Between the opposed flange portions 35 of bushings 34 and keyed to shaft I6 as at 36 is an eccentric 31. The outer periphery is suitably formed to seat balls 38 and these bear upon the exterior ring structure 39 retained by cage 40, the exterior of which may be hardened, if desired.

The side walls 2'I are relieved as at 4I and extending forwardly from the body portion is the channel cap portion 42. The reclprocable member 32 projects into this space and rigid tion 43.

As the eccentric rotates with shaft I6, the antifriction structure tends to rotate so that cage 40 contacting the interiorof loop 43 causes member 32 to reciprocate.

'I'he lower end of member 32 is exposed through the loweropen end of the channel. Member 32 is cut away as at 44 to detachably mount the movable shear blade 45 by means of-screws 46. The cutting edge is inclined upwardly and forwardly as shown in Fig. 2 and rearwardly from the cutting edge as shown in Fig. 3. The extreme and exposed lower end of member 32 is similarly formed as at 41, and forms a reenforc-` ing continuation of blade 45.

well as others which will readily suggest them-v Thus, the work can be moved from left to rightsee Fig. 2-or the attachment can be forced into work being cut but in an opposite direction. In

this relative movement the work adjacent the cut is supported by foot 29. The portion 28 divides the pieces and thus interference therewith is eliminated, as the cut is continued. Another adjusting screw 60 is carried by one wall 21 and member 32 rides thereon. Thus, shear blade- 45 can also be adjusted relative to shear portion'50.

Inv Fig. 6 a modified form of foot structure is illustrated. Numerals of the one hundred series similar to those of the primary series indicate like or similar parts.

Herein the toe .portion I 48 of foot |29 is curled inwardly and thence rearwardly as indicated by numerals |53 and I 54, respectively. This type of foot. arrangement holds the sheet metal substantially straight and prevents it binding or twisting relative to the shear blades in the out? ting operation.

To cut an inside circle, a hole is formed in the 1 sheet of metal and the foot screwed through 'it until the metal is properly positioned for cutting purposes.

While the invention has been illustrated and ldescribed in great detail in the drawing and fore- The several modications described herein as selves to persons skilled in this art, all are considered to be within the broad scope of the invention, reference being had to the appended claims.

The invention claimed is:

l. A shearing attachment, adapted to be driven by a portable, hand-type electric motoncomprising an elongated tubular casing of substantially rectangular outline and including a body and a cover detachably secured thereto, a shaft rotatablyl supported by the upper end of the casing in both the body and the cover, an eccentric on the shaft and retained thereon within said casing by opposite walls of the latter, an annular member surrounding said eccentric and similarly retained by the aforesaid casing walls,

and a reciprocable member having a shear sup-4 porting portion at one end and at its opposite end an elliptical portion encircling said annular member for actuation thereby, the lower portion 3. In a shearing attachment for a portable,`

hand-type electrical motor, comprising a motor operable reciprocable shear having a slantingly inclined cutting free end and an elongated casing for slidably supporting and guiding the shear, the combination of a work supporting foot rigid with one side of the casing and slantingly extending therefrom in the general direction of the shear end slanting inclination, then laterally,

then approximately transverse to the lateral portion and direction of shear reciprocation in an amount to project beyond the cutting position of the shear and then substantially parallel to the first mentioned laterally directed portion for work support fore and aft of the shear, and cooperating shear means on the transverse portion, the latter portion being arranged for work support,Y the said parallel portion having a rearwardly directed end parallel to the said transverse portion and in alignment with and spaced from the rst mentioned extended, inclined casing rigid portion.

' GAIL MCHENRY. 

